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Biomedical subjects

P Lequien

Publications and source records attributed to P Lequien.

At least 19 recordsLinked to original sources
PubMed2001

[Experimental study of changes in FiO2 during manual ventilation].

UNLABELLED: Discrepancies exist in the recommendations about the oxygen flow to deliver during manual ventilation. The aim of the present study was to determine the effects of ventilatory frequency (FR), inspiratory pressure (P) and oxygen flow on the concentration of the delivered oxygen (FiO2) to obtain FiO2 near 1. MATERIAL AND METHODS: Experimental study with self-inflating resuscitation bag (Ambu with oxygen reservoir) tested on a mono-compartmental test lung (resistant tube and elastic bag [Draeger]; characteristics: compliance = 0.6 mL/cmH2O; resistance = 85 cmH2O.L-1.s-1). Protocol 1: six neonatologists ventilated this model as if they were ventilating premature newborn infants with RDS at various ventilatory rates from 30 to 120 bpm and at various oxygen flows (from 2 to 12 L/min). Tidal volumes (Vt), inspiratory times (Ti), P and FiO2 were recorded continuously during the study. Protocol 2: a graduated manometer was added to visualize pressure. The same protocol was then applied. RESULTS: Protocol 1 (without visual control of the pressure): increase in oxygen flow delivered with the Ambu increases the FiO2 values (P < 0.0001); the higher the ventilatory frequency, the lower the FiO2 (P < 0.0001). The mean value of delivered FiO2 was related to the operator (extreme: 47-86%) (P < 0.001). Multivariate statistical analysis showed that O2 flow, ventilator rate and operator modulated independently the FiO2. Ti and Vt did not change the FiO2. Protocol 2 (with visual control of the pressure: the mean inflating pressures were less than those obtained without visual control of the pressure (26 vs 40 cmH2O respectively; P < 0.05). FiO2 was independent of O2 flow and ventilatory rate. CONCLUSIONS: A special device for continuous visual control of airway pressure is recommended during neonatal manual ventilation. It prevents ventilatory rate-induced FiO2 fluctuations and overdistention.

Equipment Design↗
PubMed2000

[Co-sleeping and sudden infant death syndrome].

Bedsharing has recently become a controversial subject. Some authors, mainly from North America, assign to bedsharing a positive effect on the efficacy and duration of breast-feeding. Moreover, it would protect against sudden infant death syndrome (SIDS). Conversely, other studies consider bedsharing as an additional risk factor for SIDS. From the literature data, there is some evidence for an increased risk of SIDS when bedsharing is associated with maternal smoking and alcohol consumption. Bedsharing cannot be recommended as an absolutely safe practice. Breast-feeding mothers should be aware of these potential hazards.

Adult↗
PubMed2000

[Congenital hernia of the diaphragm. A retrospective study of 123 cases recorded in the Neonatal Medicine Department, URHC in Lille between 1985 and 1996].

BACKGROUND: During the last ten years, new therapeutic strategies have been used in order to improve the management of congenital diaphragmatic hernia (CDH). CDH is associated with pulmonary hypoplasia, abnormal pulmonary vascular reactivity and pulmonary immaturity. Between 1985 and 1990, mechanical hyperventilation and early surgery were provided systematically. Since 1991, the management of CDH in our institution has involved a preoperative stabilization with exogenous surfactant replacement, gentle ventilation, high-frequency oscillation, nitric oxide or extracorporeal membrane oxygenation. PURPOSE: To analyse the impact of the new therapeutic strategy on the survival and outcome of newborns with CDH. METHODS: Retrospective review of all infants with CDH admitted to our institution from 1985 through 1996. Mortality and morbidity were compared between period I (1985-1990) and period II (1991-1996). RESULTS: Between 1985 and 1996, 123 neonates were admitted to our Neonatal Department. Nine of them had another severe congenital malformation and were excluded from the study. Survival was 23% (12/52) in period I and 56% (35/62) in period II (p < 0.001). In period II, complications were more frequent among survivors in whom an extracorporeal membrane oxygenation was required (13 infants): bronchopulmonary dysplasia 77% (10/13), gastroesophageal reflux 61% (8/13), and hypotrophy 61% (8/13). CONCLUSION: These data demonstrate a significant improvement in survival in CDH since the implementation of new therapeutic modalities. Nevertheless, a significant morbidity exists among the infants who survive a severe respiratory failure.

Bronchopulmonary Dysplasia↗
PubMed2000

[Non-medical factors in perinatal health. A study of socioeconomic anc cultural features of women admitted to the maternity hospital in Lens (Pas-de-Calais)].

BACKGROUND: The aim of this study was to determine the influence of medical and non-medical factors on perinatal health in an underpriviledged area, the ex-coal mines of Lens (Pas-de-Calais). POPULATION AND METHODS: This prospective study concerned 1,000 women who delivered in the maternity hospital of Lens between January 5, 1993 and May 13, 1993. The relationships between preterm delivery, low birth weight and maternal socioeconomic and cultural characteristics were analyzed. RESULTS: The women included presented adverse pregnancy outcomes. Preterm delivery, low birth weight and neonatal transfer rates were respectively 6.9%, 7.3% and 12.7% higher than the average regional rates. In contrast with these results, antenatal care could be considered correct or even better. The poor socioeconomic status of the population appeared to be a very significant perinatal risk factor. CONCLUSION: At present, in an unfavourable regional conjuncture, socioeconomic and cultural factors have adverse effects on perinatal morbidity and mortality independent of medical factors like prenatal care. The prevention of poor perinatal outcome should be based on these data. Not the access to the health care system but the manner of dispensing health care should require great consideration.

Adult↗
PubMed2000

Effects of inhaled nitric oxide on gas exchange and acute lung injury in premature lambs with moderate hyaline membrane disease.

OBJECTIVE: The purpose of this study was to examine whether inhaled nitric oxide (iNO) may change lung injury in moderate hyaline membrane disease (HMD). METHODS: Fifteen moderately premature lambs (128 days gestation, term=147 days) were randomly assigned to treatment with 20 ppm inhaled NO (n=7) from the onset of ventilation or control (n=8). Except for inhaled NO, treatments were intentionally similar to those applied in clinical situations. After porcine surfactant administration (Curosurf, 100 mg/kg), mechanical ventilator settings were modified during the course of the study to maintain PaCO(2) between 40 and 50 mmHg and post-ductal SpO(2) between 90 and 95%. The main studied parameters were gas exchanges parameters, respiratory mechanics (static compliance and functional residual capacity) and pulmonary vascular permeability and/or filtration rate indices. RESULTS: We found that 20 ppm of inhaled NO for 5 h significantly reduce ventilatory and oxygen requirements, but only during the first hour of mechanical ventilation. No increase in extravascular lung water content (5.41+/-0.96 vs. 5.46+/-1.09 ml/g bloodless dry lung in the control group and in the NO group, respectively) and no impairment of the respiratory mechanics could be found in the NO-treated group. However, inhaled NO increased the albumin lung leak index in this model (6.09+/-1.51 in the NO-treated group vs. 4.08+/-1.93 in the control group; P<0.05). CONCLUSIONS: Our results do not therefore support a detrimental effect of short-term exposure to low doses of NO inhalation in moderate HMD. However, it may induce an increase in lung vascular protein leakage. The pathophysiological consequences of this finding remain to be elucidated.

Administration, Inhalation↗
PubMed2000

Two years' follow-up of newborn infants after extracorporeal membrane oxygenation (ECMO).

OBJECTIVE: Extracorporeal membrane oxygenation (ECMO) is a technique of extracorporeal oxygenation used in newborn infants with refractory hypoxemia after failure of maximal conventional medical management, when mortality risk is higher than 80%. We retrospectively reviewed all the neonates treated by ECMO between October 1991 and September 1997 in our newborn intensive care unit. METHODS: Fifty-seven patients were treated with ECMO for severe respiratory failure: congenital diaphragmatic hernia (CDH) (n=23), neonatal sepsis (NS) (n=14), meconium aspiration syndrome (MAS) (n=12), and others (n=8). Mean gestational age and birth weight were 38+/-2 weeks and 3200+/-500 g, respectively. Oxygenation index was 61+/-8. Both venovenous (n=28) or venoarterial ECMO (n=29) were used. The mean time at ECMO initiation was 47 h (range 8 h-2 months). The mean duration was 134+/-68 h. In each case of VA ECMO, carotid reconstruction was performed. Survival at 2 years was 40/57 (70%) (CDH 12/23 (52%), NS 11/14 (79%), MAS 12/12 (100%), others 5/8). Follow-up at 2 years was available in 36 survivors. RESULTS: Neurodevelopmental outcome was not related to the initial diagnosis: normal neurologic development (n=30), cerebral palsy (n=5), and neurologic developmental delay (n=1). Two patients remained oxygen dependant at 2 years, and four required surgical treatment for severe gastroesophageal reflux. Respiratory and digestive sequelae were more frequent in the CDH group (P<0.01). Patency and flow of the repaired carotid artery was assessed in 20 infants at 1 year of age using Doppler ultrasonography: normal (n=10), <50% stenosis (n=9), and >50% stenosis (n=1). CONCLUSION: ECMO increased survival of newborn infants with refractory hypoxemia. However, higher a survival rate and lower morbidity were found in non-CDH infants than in congenital diaphragmatic hernia.

Brain Ischemia↗
PubMed2000

Combined effects of inhaled nitric oxide (iNO) and oxidant agents on the production of methemoglobinemia in newborn piglets.

OBJECTIVE: To investigate the effects of the association of inhaled nitric oxide (iNO) and oxidant drugs (acetaminophen, phytomenadione, and EMLA cream) on methemoglobinemia during the neonatal period. DESIGN: Prospective, randomized, experimental study. SETTING: University Experimental Pharmacology laboratory. SUBJECTS: Sixty newborn piglets weighing 1.5-2.0 Kg. INTERVENTIONS: Twelve groups of five piglets were anaesthetized, mechanically ventilated, and studied for 3 hrs. Eight groups received iNO (40 ppm or 80 ppm) alone or in association with a single intravenous dose of acetaminophen (120 mg/kg propacetamol), phytomenadione (5 mg vitamin K1) or EMLA cream (2.5 g) applied to the ventral lower abdomen for 3 hrs. Three other groups received, respectively, acetaminophen, phytomenadione, or EMLA cream without iNO. The last group (control group) received neither drugs nor iNO. MEASUREMENTS AND MAIN RESULTS: Methemoglobinemia was measured before the beginning of each experiment, 30 mins later, and every hour for 3 hrs. There was no significant difference in methemoglobinemia at any time between groups receiving acetaminophen (0.90%+/-0.12%), phytomenadione (0.88%+/-0.11%), or EMLA cream alone (0.97%+/-0.11%) and the control group (0.92%+/-0.12%). At 3 hrs, methemoglobinemia was slightly but significantly increased in group receiving iNO alone (1.04%+/-0.17% at 40 ppm iNO and 1.14%+/-0.16% at 80 ppm iNO; p < .05). Conversely, methemoglobinemia increased as a function of time in groups in which iNO was associated to drug administration and was significantly greater than the control group at 3 hrs (80 ppm iNO + acetaminophen, 2.80%+/-0.47%; 80 ppm iNO + phytomenadione, 2.38%+/-0.45%; 80 ppm iNO + EMLA cream, 2.33%+/-046%; p < .001). CONCLUSIONS: These results demonstrate that if oxidant drugs (acetaminophen, phytomenadione, or EMLA cream) did not increase blood methemoglobinemia in neonatal piglets, their association with iNO caused an increase in methemoglobin. Special care should be taken to monitor methemoglobinemia when iNO is combined to such drugs in newborn infants.

Acetaminophen↗
PubMed1999

Comparison of four methods for measuring elevation of FRC in mechanically ventilated infants.

The aim of the study was to compare measurements of the elevation of functional residual capacity (FRC) above the relaxation volume obtained in 34 mechanically ventilated infants (median weight 2.6 kg, range 1.2-9) from four different methods: (1) direct measurement of the complete exhalation volume after brief disconnection from the ventilator, (2) calculated measurement from total positive end-expiratory pressure (PEEP) measured by end-expiratory occlusion of the breathing circuit, (3) extrapolated evaluation from the mathematical model of Brody, (4) extrapolated evaluation from the passive expiration method. We considered the direct measurement (1) as the "gold standard". Measurements obtained by total PEEP (2) and by the Brody's mathematical model (3) provided similar results than the direct measurement. Conversely, graphical extrapolation from the passive expiration method (4) underestimated the elevation of FRC. In conclusion, we suggest using the mathematical extrapolation from the Brody's model to evaluate the elevation of FRC in mechanically ventilated infants: this method is non-invasive, does not require disruption of gas flow, can be easily performed with all the neonatal ventilators, and allows continuous breath-by-breath measurements.

Airway Resistance↗
PubMed1999

[Use of double-lumen umbilical vein catheters in a neonatal intensive care unit].

BACKGROUND: The aim of the study was to compare the success/failure rate and complications of insertion into the umbilical vein, of either double-lumen catheters (Charrière diameter 04, length 13 and 30 cm) or single-lumen catheters (Charrière diameter 05, length 40 cm) in a population of neonates admitted to a neonatal intensive care unit. The numbers of insertions of additional peripheral venous catheters were also compared. PATIENTS AND METHODS: The population was divided into two groups according to the severity of the respiratory failure. Group 1 (n = 52): normal hemodynamic parameters and moderate respiratory failure (FiO2 < 0.6): only single-lumen catheters were used. Group 2 (n = 56): low systemic pressure requiring vascular filling and/or inotropic drugs infusion and/or severe respiratory failure (FiO2 > 0.6): in this group, either single-lumen catheters or double-lumen catheters were inserted. RESULTS: The success rate of insertion of double-lumen catheters and of single-lumen catheters were similar (61% vs 71%: P = 0.7). Nineteen double-lumen catheters were inserted in the group 2. The average duration of double-lumen umbilical catheterization was not significantly different from simple-lumen catheterization (4.9 +/- 2.2 vs 4.6 +/- 2.2 days). Complications relating to the umbilical venous catheterization were uncommon: three catheter obstructions (two with single-lumen catheter, one with double-lumen catheters), two nosocomial infections (both with single-lumen catheter), one hydropericardium (with single-lumen catheter). In group 2, more peripheral venous catheters were required during the first 72 hours of life after insertion of single-lumen catheter than after insertion of double-lumen catheters (average number of peripheral venous catheters per infant: 1.6 +/- 0.83 vs 1 +/- 0.35 respectively; P < 0.01). CONCLUSION: Feasibility and complication rate of umbilical double-lumen catheters were similar to those of single-lumen catheters. The use of umbilical double-lumen catheters reduces the need of peripheral venous catheters.

Cardiotonic Agents↗
PubMed1999

[Prematurity and sudden infant death syndrome. Polysomnography in question].

Systematic recording of cardiorespirographic events has been recommended by some authors in premature and/or very low birth weight infants before or shortly after hospital's discharge. Their objective is the recognition of babies at risk of sudden infant death syndrome (SIDS) and prevention by home monitoring. After an extensive review of the recent literature, prematurity itself does not appear as a risk factor of SIDS. Late apneas are common, but their prognostic significance remains uncertain. Although it is clear that bronchopulmonary dysplasia carries a greater risk of acute life threatening events and infantile death, their prevention mainly relies upon an adequate oxygen supplementation. As a consequence no more than the general infant population, premature infants require neither polysomnographic recording nor home monitoring.

Humans↗
PubMed1999

[For or against the early use of nasal continuous positive pressure and exogenous surfactant in hyaline membrane disease. Physiopathologic arguments].

The use of nasal CPAP in the treatment of respiratory distress syndrome in very premature newborns follows pathophysiological basis. The authors emphasize the usefulness of nasal CPAP and surfactant in the treatment of respiratory distress syndrome. The aim of this strategy is to reduce alveolar atelectasis, thus reducing the incidence and the severity of respiratory distress syndrome, together with a possible reduction of the incidence of bronchopulmonary dysplasia.

Bronchopulmonary Dysplasia↗
PubMed1999

Combined effects of inhaled nitric oxide and hyperoxia on pulmonary vascular permeability and lung mechanics.

OBJECTIVE: To determine whether inhaled nitric oxide (NO) may alter pulmonary vascular permeability and respiratory function in an in vivo model. DESIGN: Prospective, randomized, controlled, experimental study. SETTING: University experimental pharmacology laboratory. SUBJECTS: Mechanically ventilated newborn piglets, 1 to 2 days old, exposed to 100% oxygen for 76 hrs. INTERVENTIONS: The piglets were randomly assigned either to a treatment group receiving 20 ppm inhaled NO from the onset of ventilation (n = 5) or to a control group (n = 6) receiving no treatment. MEASUREMENTS AND MAIN RESULTS: The main variables studied were gas exchange (PaO2/F(IO2) ratio, lung diffusing capacity), respiratory mechanics (static compliance of the respiratory system, stat, quasi-static hysteresis area, functional residual capacity), and pulmonary vascular permeability assessed by simultaneous intravenous administration of iodine-125-labeled albumin and chromium-51-labeled red blood cells. Extravascular albumin space of the lung and dry lung weight were significantly higher in the NO group vs. the control group (albumin space, 1.08+/-0.16 vs. 0.70+/-0.26 [SD] mL/kg body weight [p < .05]; dry lung weight, 3.20+/-0.34 vs. 2.66+/-0.14 g/kg body weight [p < .05]). Moreover, the hysteresis area was higher from 24 hrs of NO exposure. Conversely, NO inhalation altered neither the extravascular lung water content (12.98+/-2.79 mL/kg body weight in the NO group vs. 12.18+/-2.26 mL/kg body weight in the control group [not significant]) nor the main respiratory mechanical variables (static compliance, functional residual capacity) and gas exchange (lung diffusing capacity, PaO2/F(IO2) ratio). CONCLUSION: These results do not support the hypothesis that NO inhalation combined with hyperoxia can alter the main lung-function variables in neonates. However, it may induce an increase in lung vascular protein leakage. The pathophysiologic consequences of this finding remain to be elucidated.

Administration, Inhalation↗